Understanding how sensory inputs are dynamically mapped onto the functional activity of neuronal populations and how their processing leads to cognitive functions and behavior requires tools for non-invasive interrogation of neuronal circuits with high spatiotemporal resolution. A number of approaches for three dimensional (3D) neural activity imaging that take advantage of chemical and genetically encoded fluorescent reporters exist. Whereas some are based on scanning the excitation light in a volume, either sequentially or randomly, others try to capture 3D image data simultaneously by mapping axial information onto a single lateral plane.
Light-field microscopy (LFM) is one such simultaneous 3D imaging method that has been applied to non-biological and fixed biological samples. However, despite its potentially superb temporal resolution, LFM has not generally been used for functional biological imaging. This is because capturing the light-field information via a single sensor image comes at the cost of reduced spatial resolution and because of inherent trade-offs between axial imaging range and the spatial and axial resolution.
A need therefore exists for methods for providing simultaneous functional imaging of phenomena at high magnification levels, for large sample sizes and at high resolution, for example for recording neuronal activity at single-neuron resolution in an entire caenorhabditis elegans (C. elegans) and in larval zebrafish brain. Specifically, a need exists for high-speed, high resolution, large-scale 3D imaging at high magnification levels capable of recording time dynamics of systems at very small scales, including biological systems.